In attempting to dissect the various cellular events responsible for the development of EAE, we have studied the effect of in vitro culture with antigen on the ability of BP-sensitized cells to transfer EAE to naive recipients. Two different cell compartments, peritoneal exudate cells, PEC, and lymph node cells, LNC, display distinctly different responses to BP in culture. The ability of both populations of cells to transfer EAE is enhanced after culture with antigenic but the LNC require an additional signal in culture. This difference is being exploited to identify the subpopulations of T cells responsible for EAE induction and the role they play in regulation of this autoimmune cell mediated disease.